1. Field of the Invention
The present invention relates to a storage device having a data-readable/writable storage medium and to an information processing system.
2. Description of the Related Art
Information processing apparatuses, such as personal computers and PDAs (personal digital assistants), generally have a storage device, such as an HDD (hard disk drive), for storing various items of data including, for example, file system and security data. Additionally, the apparatuses use demountable storage devices.
Various techniques have hitherto been proposed in the field of storage devices of the type described above. For example, Jpn. Pat. Appln. KOKAI Publication No. 6-282386 describes a highly reliable disk storage system. In the disk storage system, nonvolatile memories are used as cache memories for a magnetic disk, in which in the event of an apparatus reboot after failure occurrence resulted from, for example, a momentary mains-power failure, cache data stored in the nonvolatile memories are used to renew or update the content of data stored in a magnetic disk.
However, in disk storage systems of the type described above, while the storage capacity is relatively large, there arises a problem in that an average overhead time is increased due to delay time called “latency”, seek time, or the like. In addition, there arises another problem in that the power consumption is high.
Under these circumstances, the presentation is demanded for techniques that reduces the average overhead time and efficiently controls data.